Showing papers by "Raphael A. Stern published in 2007"

The Appropriate Management of Honey Bee Colonies for Pollination of Rosaceae Fruit Trees in Warm Climates

Abstract: Most of the Rosaceae fruit trees, such as apple, pear, plum, almond and cherry, exhibit full self-incompatibility. Therefore, their fruit production completely depends on cross pollination. The ultimate pollen carrier in Rosaceae is the honey bee. In the present review, different bee-hive management techniques for improving fruit set and yield are discussed. The main manipulations are of colony density and the timing and number of colony introductions. In pear, it was found that increasing the density from 2.5 colonies ha -1 to 5 colonies ha -1 in one introduction at 10% full bloom (FB), did not increase bee activity on the trees and did not improve fruit set and yield. However, introducing the colonies sequentially (1.25 colonies ha -1 at 10% FB and 1.25 colonies ha -1 at FB) increased bee activity and consequently improved fruit set and yield. In apple, the combination of both treatments: increasing the density to 2.5 colonies ha -1 at 10% FB and a second introduction of 2.5 colonies ha -1 at FB, for a total of 5 colonies ha -1 , increased the number of bees tree -1 , their mobility between the rows and the proportion of “topworkers” compared with “sideworkers”. As a result, fruit set and yield were enhanced. In Japanese plum, highest bee activity, fruit set and yield, were achieved when colonies were introduced at four different times (multiple introductions). Each introduction was of a density of 1.25 colonies ha -1 at 10% FB, 50% FB, FB and FB+3 days (total of 5 colonies ha -1 ). For all three species, there was a positive and statistically significant correlation between the average number of bees tree -1 and fruit set or yield. The optimum number of bees tree -1 min -1 at FB was 6-7 for pear, 7-8 for Japanese plum and 12-14 for apple.

Multiple introduction of honeybee colonies increases cross-pollination, fruit-set and yield of ‘Black Diamond’ Japanese plum (Prunus salicina Lindl.)

Abstract: SummaryJapanese plum (Prunus salicina Lindl.) belongs to the Rosaceae family, which carries the S-RNase-mediated gametophytic self-incompatibility system, which prevents self-fertilisation, and thus promotes out-crossing. The plum cultivar ‘Black Diamond’® has become, one of the most important cultivars in Israel in the last decade, yet its yield is low in comparison with its known potential. Honeybees (Apis mellifera) are the most important pollinators for plums and several studies have demonstrated an apparent relationship between the number of honeybees and the size of the fruit crop. Therefore, in this study, we focussed on improving bee management in a ‘Black Diamond’ orchard. In four consecutive years of experiments, we examined the effects of increasing the density of bee colonies, and of making multiple introductions of colonies, on honeybee activity and on their effectiveness as pollinators of ‘Black Diamond’. We showed that four separate introductions, each of 0.625 colonies ha–1, every 2 – 3 d ...

SFBs of Japanese Plum (Prunus salicina): Cloning Seven Alleles and Determining Their Linkage to the S-RNase Gene

Abstract: Japanese plum (Prunus salicinaLindl.), a species of theRosaceaefamily, carries the S-RNase-mediated gametophytic self-incompatibility system. Self-incompatibility ismanifestediftheS-haplotypeofthepolleniscarriedalsobythepollinatedflower.Thus, for fertilization to occur, the cultivars have to be genetically compatible. The haplotype is conferred by an S-locus, which contains the style-specific expressed S-RNase and the pollen-specific expressed F-box genes (SFB). Since both the S-RNase and the SFB genes are multiallelic and are characteristic of each of the S-haplotypes, they are ideal markers for molecular S-typing. In this work, seven SFBs, from eight japanese plum cultivars, were cloned and sequenced. Five of the alleles were published recently and two SFB g and SFB k are new. The physical linkage of SFB b and SFB c to their adjacent S-RNase was determined; it is 544 base pairs (bp) and 404 bp for the S b and S c loci, respectively.

Plant growth regulators increase the fruit size of 'Spadona' and 'Coscia' pears (Pyrus communis) in a warm climate

Abstract: SummaryThe two main pear cultivars grown in the warm climate of Israel, ‘Spadona’ and ‘Coscia’, produce relatively small fruit. Over five consecutive years (2001 – 2005), the application of 0.12% (v/v) BoleroTM [8.6 mg l–1 gibberellic acid (GA3) plus 6 mg l–1 2,4-dichlorophenoxyacetic acid (2,4-D) plus 6 mg l–1 naphthaleneacetic acid (NAA)] at full-bloom, caused an appreciable and significant increase in fruit size without any deformation of the calyx-end, which is typical of GA3 treatment when applied at the same phenological stage to improve fruit set. GA3 alone did not increase fruit size. Application of 0.125% (v/v) PerlanTM [25 mg l–1 benzyladenine (BA) plus 25 mg l–1 GA4+7] at full-bloom + 14 d, increased fruit size via stimulation of fruit cell division (BA) and fruit cell enlargement (GA4+7), with no negative effect on fruit shape.

The effect of synthetic auxins on fruit development, quality and final fruit size in ‘Canino’ apricot (Prunus armeniaca L.)

Abstract: SummaryThe only commercial apricot cultivar grown in Israel, ‘Canino’, produces relatively small fruit. Over three consecutive years (2003–2005), application of 25 – 50 mg l–1 2,4-dichlorophenoxypropionic acid [2,4-DP; as its butoxyethyl ester (PowerTM)], 15 mg l–1 3,5,6-trichloro-2-pyridyloxyacetic acid [3,5,6-TPA; as the free acid (Maxim®)], or 25 – 40 mg l–1 2,4-dichlorophenoxyacetic acid (2,4-D) plus 30-50 mg l–1 naphthaleneacetic acid (NAA; 0.3% – 0.5% AmigoTM), at the beginning of pit-hardening, when the widest diameter of the fruit was 25 mm, caused appreciable and significant increases in fruit size and total yield. Anatomical studies revealed that the main effect of these synthetic auxins was via direct stimulation of fruit cell enlargement. None of the above auxins had any negative effect on fruit quality, either at harvest or after 1 month of storage at 0°C, or on return yield in the following year. Two other synthetic auxins formulations: 2,4-D (HadranolTM) and 2,4-dichlorophenoxypropionic aci...

Performance of ‘Coscia’ pear (Pyrus communis) on seven rootstocks in a warm climate

Abstract: SummaryThe vegetative and reproductive performance of ‘Coscia’ pear (Pyrus communis L.) growing on seven rootstocks [OHF 69, OHF 97, OHF 513 and BP 1 (P. communis), clonal seedling (Davis AxB) of P. betulifolia, and quince BA 29 and EMA (Cydonia oblonga)] were compared over an 8-year period. The trial was conducted at the Experimental Orchard Farm Station in northern Israel, on a well-drained soil with pH 7.5. Trees were planted in December 1998 at a distance of 4.0 m 2.0 m, and trained with a central axis. The most vigorous trees were on P. betulifolia seedling, followed by BP 1 and the three OHF rootstocks (69, 97, 513). All the above rootstocks demonstrated greater vigour than quince BA 29 or EMA. The reason for this effect, at least in part, appeared to be the excellent water status (high midday stem water potential values) of trees on P. betulifolia in comparison with the other rootstocks. The highest cumulative yields per tree were harvested from trees on P. betulifolia and BP 1, followed by the thr...